This invention relates to the process for the production of 2-substituted-imidazo[4,5-c]pyridines useful for modifying the balance between bone production and bone resorption in a host animal, including man.
Osteoporosis is a skeletal disorder which is evidenced by an increase in fracture incidence resulting from a decrease in bone density. In fact, both the bone mineral (calcium phosphate called "hydroxyapatite") and the bone matrix (major protein called "collagen") are lost. This condition may begin to occur in humans as early as age 30. In general, the process is more rapid in postmenopausal women than in men. However, after age 80 there is no sex difference in the incidence of osteoporosis. In the course of 10 to 20 years of bone loss there may be symptoms of back pain and X-ray evidence of deformation of the spine. At older ages, the brittleness of the bones becomes evident by the ease with which the proximal femur ("hip") fractures. Osteoporosis is the most common cause of fractures in people over age 45.
Although the cause of osteoporosis is poorly understood, it is believed that there is an imbalance between bone production and bone resorption (bone breakdown). Bone remains a dynamic tissue throughout the life of an animal. That is, new bone is continuously being formed and old bone is continuously being resorbed. However, in animals suffering from an osteoporotic condition, net bone resorption exceeds bone formation.
The present invention relates to the improved production of 2-substituted-imidazo[4,5-c]pyridines useful for the treatment of osteoporotic conditions. Said compounds are disclosed in Santilli, et al. U.S. Ser. No. 07/454,556, filed Dec. 21, 1989 and now abandoned. Santilli, et al. also disclose pharmacological data illustrating the utility of said 2-substituted-imidazo[4,5-c]pyridines in the treatment of osteoporotic conditions.